Weather proofing log posts & rafters

[1938farmall]

Built an open shed with peeled aspen posts on top of concrete piers & log rafter ends and need water repellent advice.  I did a search here for home remedies and went to the Forest Prod.Lab. site - looks like they are all about the same concoctions of spar varnish, paraffin, and solvent.  Was interesting that the gent writing from FPL said he would not use the home-brew on his own deck, but would choose a commercial product (which he didn't/couldn't name).  Since Penta is history, does anyone have a brand name suggestion or another home-brew that you are really happy with?  Thanks in advance.  al

[jander3]

Large overhangs and keep the logs covered works best. 

I've used penetreat (for bugs), I've coated logs exposed to the weather with motor-oil.  I have a log swing that I coated with motor oil 10 years ago, it's sat on the ground out in the weather and still no rot.

I know some guys that use PQ-80 and then coat the logs with a stain or finish.  Below is info on PQ-80 (source = www.schoolofologbuilding.com). 

Because there has been some confusion about the source for one of the post-log-peeling biocide products, PQ-80, here's the skinny:
5 gallons of the PQ-80 concentrate (a several years' supply that several builders could share) is currently $284.40, plus shipping, which is less to a commercial address than to a residence. The accompanying "Adjustabor" liquid borax product is $50.00 for 5 gallons. ISK Biocides' (the manufacturer and sole sourse) customer service number is 1.800.238.2523. Even though your usable mixture is mainly water, it is toxic. Never have it where pets or children can access it, wear protective rubber gloves, and carefully follow all of the manufacturer's directions. This is not a preservative as such, but will prevent some of the formation of fungus, molds, sapstains etc. on your freshly peeled building logs.

[shinnlinger]

I thought this looked interesting... From terry king....

These are a combination of ethylene glycol (auto antifreeze) and borate.  You CAN make it yourself for a lot less money...

-- The whole article on this is here:   
http://terryking.us/boatbuilding/RotEthyleneGlycol.html

This is aimed at boatbuilding and I've used it extensively for that.  But I also use it (plain ethylene glycol antifreeze) successfully on exposed porch floorboards, outhouse flooring, and on parts of the 32x32 foot timber framed barn I built 5 years ago in Vermont.  I especially hit the lap joints in the sills (8x8 hemlock) every year. I also soaked all the lap joints, and all the post pockets with glycol a couple times before assembly.  And I have  2 removable floor sections for a truck-repair pit that accumulate a lot of sawdust, dirt and water over a winter.. Once a year I have blown them clean and soaked the mating areas with glycol.  Clean as a whistle after 5 years.. And there is no green or growing stuff on the sill joints either.  I just use a hand sprayer, and wash my hands afterward.. Not highly toxic like other chemicals. 

"Works For Me"....

----------------( extract: How-To part from Dave Parnell )-----------------
      BORATE WOOD PRESERVATIVES:
      COMMERCIAL AND HOME-BREWED       

          Tim-Bor®: Solid sodium octaborate; dissolves in water to make
          approx. a 10% solution containing 6.6% borate (B2O3); about
          $3/lb. plus shipping.
          Ship-Bor®: Same as Tim-Bor®; $19.95/lb. plus $2 shipping.
          Bora-Care®: 40% solution of sodium octaborate in ethylene
          glycol; 27% borate content; $70/gal. plus shipping.

          Home-Brew Water Solution of Borates:

              Based on U.S. Navy spec. of 60% borax-40% boric acid (this
              ratio gives the maximum solubility of borates in water);
              65% water, 20 %borax, 15% boric acid; 15.8% borates; borax
              costs 54 cents/lb. (supermarket), boric acid costs about
              $4/lb. in drug stores (sometimes boric acid roach poison,
              99% boric acid, is cheaper in discount stores); equiv. to
              Tim-Bor® or Ship-Bor® at 30 cents/lb. To make this
              solution mix the required quantities and heat until
              dissolved. The boric acid, in particular, dissolves
              slowly. This solution is stable (no crystals) overnight in
              a refrigerator (40°F.), so can be used at temperatures at
              least as low as 40°F.

          Home-Brew Glycol Solution of Borates:

              This is equivalent to Bora-Care® diluted with an equal
              volume of glycol to make it fluid enough to use handily;
              50% glycol antifreeze, 28% borax, 22% boric acid. To make
              a stable solution you mix the ingredients and heat till
              boiling gently. Boil off water until a candy thermometer
              shows 260°F. This removes most of the water of
              crystallization in the borax. This solution is stable at
              40°F and has a borate content of 26%. With antifreeze at
              $6/gal. and borax and boric acid prices as above, this is
              equivalent to Bora-Care® at about $15/gal.
----------------( end extract: How-To part from Dave Parnell )-----------------

Dave is a retired DuPont chemist who has done a lot of personal research on this subject.

-- Toxicity?? We all know ethylene glycol antifreeze is toxic to us and all mammals.  So make sure there is no remaining liquid left for animals. It absorbs pretty quickly into wood. Here's Dave Parnel's take on toxicity:
---(copy)---
          Glycol's toxicity to humans is low enough that it has to be
          deliberately ingested (about a half cup for a 150 lb. human);
          many millions of gallons are used annually with few
          precautions and without incident. It should not be left where
          children or pets can get at it, as smaller doses would harm
          them, and they may be attracted by its reported sweet taste
          that I have confirmed by accident. The lethal dose of borates
          is smaller than of glycol, but the bitter taste makes
          accidental consumption less likely.
---( end copy)---
Note: There is a movement in USA to require a bittering agent to be added to auto antifreeze.

Hope this is useful to some people...

[1938farmall]

thanks guys, that's heavy duty info.   my eaves are at least 4' and 11' high.

[PineNut]

I have been using the Bora-Care equivalent for a couple of years and it works much better than the Tim-Bor equivalent. My mixtures are as in the post above by shinnlinger.

Mix ratios will depend on the type and how dry the lumber is. I have used from 1:1 to 1:4 with green hardwood being 1:1 and dry pine 1:4.

I have two problems with the Tim-Bor equivalent. When it is applied to the surface, the surface dries rather quickly and leaves crystals on the surface. Crystals on the surface don't provide much protection. I would expect if you kept the surface damp for a while, more of the chemical would get into the wood. The other problem is that it will crystallize rather quickly. That makes for problems if you attempt to spray it.

The Bora-Care equivalent does not give me any problems with crystallization. Also the surface of the lumber will stay damp much longer giving the chemicals time to move into the wood and no crystals are left on the surface.

I have not done any tests to see how well the treatment works. Guess I should take some treated wood and place it close to some wood known to have power post beetles. Has anyone done any test as to the effectiveness of this treatment?

I have used two methods of application. One is spraying. This is a pain to keep the solution clean enough not to clog the sprayer. Lately I have been using a paint brush and roller. This seems to go faster than having to clean out the sprayer. I would like to dip the lumber but that would take a large amount of solution to prime the tank. Currently considering a trough with the lumber supported over it. Use a pump and hose to flow the solution over the lumber. 

[WAGZ]

the ridge pole and purlins come out the gable ends of my house for accents, they are covered by some fairly large eaves, but I am going to take some extra precautions, and as far as I can tell, "impell rods" seem like the best solution, but I have no real experience with them as of yet........

I would have to agree with jaunder3, big overhangs are the best prevention....

[earlybird]

Hello there, I have a question about the Bora-Care equivalent mentioned above.  I am considering treating the pine posts of the Gazebo that I am building and I`m wondering if one could stain and or varish the wood after treating it.  In other words does the Bora-care discolour the wood?  If so, what does it end up looking like?  Thanks